package com.njlime.core.helper;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

/**
 * 以静态变量保存Spring ApplicationContext, 可在任何代码任何地方任何时候中取出ApplicaitonContext.
 * 
 * @author xubin
 */
public class SpringContextHolder implements ApplicationContextAware {

	private static ApplicationContext applicationContext;

    /**
     * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
     */
    public void setApplicationContext(ApplicationContext applicationContext) {
            SpringContextHolder.applicationContext = applicationContext; //NOSONAR
    }

    /**
     * 取得存储在静态变量中的ApplicationContext.
     */
    public static ApplicationContext getApplicationContext() {
            checkApplicationContext();
            return applicationContext;
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) {
            checkApplicationContext();
            return (T) applicationContext.getBean(name);
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     * 如果有多个Bean符合Class, 取出第一个.
     */
    public static <T> T getBean(Class<T> requiredType) {
            checkApplicationContext();
            return applicationContext.getBean(requiredType);
    }

    /**
     * 清除applicationContext静态变量.
     */
    public static void cleanApplicationContext() {
            applicationContext = null;
    }

    private static void checkApplicationContext() {
            if (applicationContext == null) {
                    throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");
            }
    }
	
}
